An Introduction to Temperature Data Loggers
What is temperature data logging? Temperature logging is used in many industries where it is vital to know and keep a record of the temperatures that a product has been exposed to. Prominent examples of this are food transportation, where a cold chain may need to be maintained at a steady temperature, or the storage of medicines, where temperature variations can be detrimental to the product.
There are many situations where temperature loggers can be beneficial, such as in commercial settings as well as several alternative settings, including monitoring river and ocean temperatures over the long term, to help monitor environmental health and climate change.
The food industry uses temperature loggers to check food has been sufficiently heated before canning. Hospital settings use loggers to ensure that autoclaves reach the appropriate temperatures to destroy viruses and bacteria.
These are just a few examples of when temperature data needs to be monitored and logged. These records can provide evidence that proper procedure has been followed in the event of a challenge. To achieve this record, temperature data loggers are used.
What is a Temperature Data Logger?
A temperature data logger is an electronic device that has been optimised for monitoring temperature, often with external probes or sensors. Often these devices also have additional abilities, such as humidity data logging, which may require additional probes.
These temperature recorders are most commonly battery-operated. There are many flavours of devices, but one of the most popular types is the wireless temperature data logger. The term ‘wireless temperature logger’ refers to the device’s bluetooth/radio signal/WiFi internet connection.
For the non-wireless temperature monitors, data is collected manually from the logger after a chosen period of time has elapsed. The data will be downloaded ito a PC via USB cable for analysis, while the wireless temperature logger allows remote temperature monitoring & uploading of data for analysis; saving the need for field visits.
Temperature Logger Types
All data loggers, whether they are USB temperature data loggers or wireless, are essentially the same, comprising a temperature sensor attached to a recording system. The recording system samples the sensor at intervals and stores the resulting data.
For air temperature recordings, digital temperature loggers can have built-in sensors or use a number of wired probes. There are specialist sensors needed to record temperatures within fridges, using Glycol bottles mimick how a fluid such as a vaccine would react to changes in air temperature.
There are even single-use devices that can run for 90 days that are designed to be perfect when manufacturers need to send products overseas and are unlikely to get the device back. These are ideal for sea container shipping, long haul routes and other Cold Chain and Frozen shipments.
How do Temperature Loggers Work?
Temperature data loggers are generally lightweight devices, thanks to the integration of thermistors or thermocouples directly to a logging device. This small package makes it ideal for shipments where logging the temperature is a requirement in order to guarantee that your shipment has been correctly transported and that your product is appropriately fresh upon receipt.
With Thermocouple Input
Some temperature loggers accept multiple inputs from probes and also have a built-in thermocouple. A thermocouple is a sensor with two dissimilar metal wires, joined at one end to form a junction, and connected to a thermometer. When the junction is heated or cooled, a small and measurable voltage is generated. The voltage corresponds to a temperature, which is recorded by the data logger.
Thermocouples are commonly used for extreme heat and cold and are usually chosen with long cable lengths so the logger is outside of the process and not exposed to temperatures which could damage it. If short thermocouples are used, the logger is normally enclosed within a protective barrier.
The Benefits of an External Probe
For environments where the temperature is too extreme for thermocouple-based devices, a temperature probe can be attached to the device. This allows the recorder part of the device to remain safely in a moderate temperature area while the probe remains in high or low-temperature environments. Monitoring the inside temperature of ovens or supercooled fluids benefit from this arrangement.
Multi-channel Temperature Loggers
Some universal data loggers can have up to 48 single-ended inputs. They will accept input from thermistors and thermocouples, as well as a range of other types of temperature sensors.
There are three primary ways that temperature data loggers communicate their results:
- USB temperature data loggers – These devices store data on an internal drive and then act as an external hard drive. Plug them into a PC, and it is possible to simply copy the data to your device.
- Wireless bluetooth temperature data loggers – Bluetooth enabled data loggers to use Bluetooth Low Energy technology to transmit data over a 100-foot range wirelessly. These are particularly useful in areas with limited access.
- Wi-Fi temperature data loggers – Some loggers use Wi-Fi. This results in a shorter range, higher energy consumption device, which will usually only be found on devices that are plugged into mains power.
Air temperature measurement is important in a wide range of applications, ranging from monitoring changing weather and climate conditions to verifying that hygienic sterilisation procedures have been maintained. Sometimes monitoring occurs long-term in order to access trends. Other times, the primary concern is to know the minimum or maximum temperatures attained during a short period.
Humidity and Temperature logging
Humidity and Temperature data logging tend to go hand in hand, as the effects of humidity can change the way things act at different temperatures. Think about all the products that have instructions to store them in a cool, dry place. The two go hand in hand, as heat or moisture can both cause problems individually and in concert.
In facilities management, a record of temperature and humidity variation is essential in preventing inefficiencies from creeping in. The record of temperature and humidity data loggers provides a history of the experienced conditions at the site over an extended period.
A recording device intended to work in temperatures in excess of 80°C (176°F) is generally considered a high-temperature data logger. These are common in the food and health sectors. High-temperature environments include autoclaves, pasteurisation, and food and material processing. As discussed above, loggers for such environments often use a probe to allow the sensitive electronics of the logger itself to be kept out of hot conditions.
Cold Chain Logging
Many foods and pharmaceuticals must remain under carefully controlled, chilled conditions throughout their transport and their end-point storage. This is referred to as Cold Chain. Including a temperature data logger with the transported materials creates a record of the conditions experienced by the shipment.
Look for Time-saving Features
You’ll want to make sure that the temperature data logger you select has a set of features that will benefit you and make field deployment reliable and straightforward. Look for some key features:
- Memory Capacity – If you are leaving the devices for extended times, do they have the capacity to store enough data for your requirements?
- Durability – If you plan to put your data loggers into rough situations, be sure to look for rugged designs that will last.
- Bluetooth Capability – Using Bluetooth to offload data to your field device is easier than USB and prevents damage to wires or ports.
- Visual Display – Is there an LCD to allow easy viewing of current data?
- Start/Stop buttons – Being able to Start/Stop/resume on the fly is a great help out in the field.
- Deployment flexibility – Do they have a range of mounting options, such as adhesives, Velcro straps or mounting systems?
- Bundled Software – Look for software that provides useful, meaningful results.
With such a wide range of products available, it can be initially overwhelming to know which one is right for your industry. With the help of this guide, hopefully, you have begun to identify the right product for you, but if you require additional support, or are thinking about a bulk order, simply reach out to our friendly team for assistance.